, our preliminary taste data suggest that the range of response is tied to how much mRNA is expressed from the active (PAV) form of the receptor, a concept called allele-specific expression (12). For example, this is the case when analyzing caffeine consumption, which strongly correlates with active mRNA expression (12). The investigators therefore hypothesize that the abundance of active TAS2R38 mRNA in heterozygous individuals also predicts the biologically significant change in magnitude of defensive responses in the presence of AHLs (13-15). The proposed study will determine whether this is in fact the case, and whether those people who have high mRNA abundance in taste tissue (fungiform papillae) also have correspondingly high abundance in nasal epithelium, or whether regulation is tissue-dependent. This will allow us to determine whether taste tests could provide a reliable representation of receptor function in other tissues and cell types. Should mRNA abundance prove to be a key factor, the investigators will determine whether high expressers sustain this expression over time.